Piping, tubing and fittings shall comply with the applicable referenced standards, specifications and performance criteria of this code and shall be identified in accordance with Section M1301.2. Piping, tubing and fittings shall either be tested by an approved third-party testing agency or certified by an approved third-party certification agency.
A permanent factory-applied nameplate(s) shall be affixed to appliances on which shall appear, in legible lettering, the manufacturer’s name or trademark, the model number, a serial number and the seal or mark of the testing agency. A label also shall include the following:
- Electrical appliances. Electrical rating in volts, amperes and motor phase; identification of individual electrical components in volts, amperes or watts and motor phase; and in Btu/h (W) output and required clearances.
- Absorption units. Hourly rating in Btu/h (W), minimum hourly rating for units having step or automatic modulating controls, type of fuel, type of refrigerant, cooling capacity in Btu/h (W) and required clearances.
- Fuel-burning units. Hourly rating in Btu/h (W), type of fuel approved for use with the appliance and required clearances.
- Electric comfort-heating appliances. The electric rating in volts, amperes and phase; Btu/h (W) output rating; individual marking for each electrical component in amperes or watts, volts and phase; and required clearances from combustibles.
- Maintenance instructions. Required regular maintenance actions and title or publication number for the operation and maintenance manual for that particular model and type of product.
Furnaces and air handlers within compartments or alcoves shall have a minimum working space clearance of 3 inches (76 mm) along the sides, back and top with a total width of the enclosing space being not less than 12 inches (305 mm) wider than the furnace or air handler. Furnaces having a firebox open to the atmosphere shall have not less than a 6-inch (152 mm) working space along the front combustion chamber side. Combustion air openings at the rear or side of the compartment shall comply with the requirements of Chapter 17.
Exception: This section shall not apply to replacement appliances installed in existing compartments and alcoves where the working space clearances are in accordance with the equipment or appliance manufacturer’s installation instructions.
Attics containing appliances shall be provided with an opening and a clear and unobstructed passageway large enough to allow removal of the largest appliance, but not less than 30 inches (762 mm) high and 22 inches (559 mm) wide and not more than 20 feet (6096 mm) long measured along the centerline of the passageway from the opening to the appliance. The passageway shall have continuous solid flooring in accordance with Chapter 5 not less than 24 inches (610 mm) wide. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present along all sides of the appliance where access is required. The clear access opening dimensions shall be not less than of 20 inches by 30 inches (508 mm by 762 mm), and large enough to allow removal of the largest appliance.
Exceptions:
- The passageway and level service space are not required where the appliance can be serviced and removed through the required opening.
- Where the passageway is unobstructed and not less than 6 feet (1829 mm) high and 22 inches (559 mm) wide for its entire length, the passageway shall be not more than 50 feet (15 250 mm) long.
Underfloor spaces containing appliances shall be provided with an unobstructed passageway large enough to remove the largest appliance, but not less than 30 inches (762 mm) high and 22 inches (559 mm) wide, nor more than 20 feet (6096 mm) long measured along the centerline of the passageway from the opening to the appliance. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the appliance. If the depth of the passageway or the service space exceeds 12 inches (305 mm) below the adjoining grade, the walls of the passageway shall be lined with concrete or masonry extending 4 inches (102 mm) above the adjoining grade in accordance with Chapter 4. The rough-framed access opening dimensions shall be not less than 22 inches by 30 inches (559 mm by 762 mm), and large enough to remove the largest appliance.
Exceptions:
- The passageway is not required where the level service space is present when the access is open, and the appliance can be serviced and removed through the required opening.
- Where the passageway is unobstructed and not less than 6 feet high (1929 mm) and 22 inches (559 mm) wide for its entire length, the passageway shall not be limited in length.
Appliances shall be installed with the clearances from unprotected combustible materials as indicated on the appliance label and in the manufacturer’s installation instructions.
Note: “A” equals the required clearance with no protection. “B” equals the reduced clearance permitted in accordance with Table M1306.2. The protection applied to the construction using combustible material shall extend far enough in each direction to make “C” equal to “A.”
FIGURE M1306.1
REDUCED CLEARANCE DIAGRAM
The reduction of required clearances to combustible assemblies or combustible materials shall be based on Section M1306.2.1 or Section M1306.2.2.
TABLE M1306.2
REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTIONa, c, d, e, f, g, h, i, j, k, l
| TYPE OF PROTECTION APPLIED TO AND COVERING ALL SURFACES OF COMBUSTIBLE MATERIAL WITHIN THEDISTANCE SPECIFIED AS THE REQUIRED CLEARANCE WITH NOPROTECTION (See Figures M1306.1 and M1306.2) | WHERE THE REQUIRED CLEARANCE WITHOUT PROTECTION FROM APPLIANCE, VENT CONNECTOR, OR SINGLE WALL METAL PIPE IS: | |||||||||
| 36 inches | 18 inches | 12 inches | 9 inches | 6 inches | ||||||
| Allowable clearances with specified protection (Inches)b | ||||||||||
| Use column 1 for clearances above an appliance or horizontal connector. | ||||||||||
| Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | |
| 31/2-inch-thick masonry wall without ventilated air space | — | 24 | — | 12 | — | 9 | — | 6 | — | 5 |
| 1/2-inch insulation board over 1-inch glass fiber or mineral wool batts | 24 | 18 | 12 | 9 | 9 | 6 | 6 | 5 | 4 | 3 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) over1-inch glass fiber or mineral wool batts reinforced withwire or rear face with a ventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| 31/2-inch-thick masonry wall with ventilated air space | — | 12 | — | 6 | — | 6 | — | 6 | — | 6 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) witha ventilated air space 1-inch off the combustible assembly | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 2 |
| 1/2-inch-thick insulation board with ventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) withventilated air space over 24 gage sheet steel with a ventilated space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| 1-inch glass fiber or mineral wool batts sandwiched between two sheets of galvanized sheet steelhaving a minimum thickness of 0.0236-inch (No. 24 gage) with aventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.019 kg/m3, °C = [(°F)-32/1.8], 1 Btu/(h × ft2 × °F/in.) = 0.001442299 (W/cm2 × °C/cm).
- Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.
- Clearances shall be measured from the surface of the heat producing appliance or equipment to the outer surface of the combustible material or combustible assembly.
- Spacers and ties shall be of noncombustible material. Spacers and ties shall not be used directly opposite appliance or connector.
- Where all clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. (See Figures M1306.1 and M1306.2.)
- There shall be not less than 1 inch between clearance reduction systems and combustible walls and ceilings for reduction systems using ventilated air space.
- If a wall protector is mounted on a single flat wall away from corners, adequate air circulation shall be permitted to be provided by leaving only the bottom and top edges or only the side and top edges open with not less than a 1-inch air gap.
- Mineral wool and glass fiber batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1,500°F.
- Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu inch per square foot per hour °F or less. Insulation board shall be formed of noncombustible material.
- There shall be not less than 1 inch between the appliance and the protector. The clearance between the appliance and the combustible surface shall not be reduced below that allowed in this table.
- All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.
- Listed single-wall connectors shall be permitted to be installed in accordance with the terms of their listing and the manufacturer’s instructions.
- For limitations on clearance reduction for solid-fuel-burning appliances see Section M1306.2.3.
For SI: 1 inch = 25.4 mm.
FIGURE M1306.2
WALL PROTECTOR CLEARANCE REDUCTION SYSTEM
Reduction of clearances shall be in accordance with the appliance manufacturer’s instructions and Table M1306.2. Forms of protection with ventilated air space shall conform to the following requirements:
- Not less than 1-inch (25 mm) air space shall be provided between the protection and combustible wall surface.
- Air circulation shall be provided by having edges of the wall protection open not less than 1 inch (25 mm).
- If the wall protection is mounted on a single flat wall away from corners, air circulation shall be provided by having the bottom and top edges, or the side and top edges not less than 1 inch (25 mm).
- Wall protection covering two walls in a corner shall be open at the bottom and top edges not less than 1 inch (25 mm).
Appliances designed to be fixed in position shall be fastened or anchored in an approved manner. In Seismic Design Categories D0, D1 and D2, and in townhouses in Seismic Design Category C, water heaters and thermal storage units shall be anchored or strapped to resist horizontal displacement caused by earthquake motion in accordance with one of the following:
- Anchorage and strapping shall be designed to resist a horizontal force equal to one-third of the operating weight of the water heater storage tank, acting in any horizontal direction. Strapping shall be at points within the upper one-third and lover one-third of the appliance’s vertical dimensions. At the lower point, the strapping shall maintain a minimum distance of 4 inches (102 mm) above the controls.
- The anchorage strapping shall be in accordance with the appliance manufacturer’s recommendations.
Appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the floor in garages. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate with a private garage through openings shall be considered to be part of the garage.
Exception: Elevation of the ignition source is not required for appliances that are listed as flammable-vapor-ignition resistant.